Mount structure for electric lamps



Feb. 14, 1950 J. E. STONE 2,497,567

uouu'r smucruns FOR mac-me was Filed April 27. 1949 Invenfov: Joseph E. Stone. b (:22 fig His A'iftc- Patented Feb. 14, 1950 MOUNT STRUCTURE non ELECTRIC Joseph E. Stone, Cleveland Heights, Ohio, assignor to General Electric Company, a corporation of New York Application April 21, casein No. 90,01:

Claims. (01. 176-39) This invention relates to electric incandescent lamps in general, and more particularly to a mount construction therefor.

There are many so-called rough service applications where an electric incandescent lamp is subjected to considerable vibrations, jars or impacts, for instance in locomotive headlights, automatic mining machinery, earth moving equipment, tractors and other like equipment. In such cases, it is highly important that the filament or light source of the lamp be so supported that the forces developed by the vibrations or shocks be sufllciently dissipated in order to prevent distortion of the hot filament such as is apt to result in premature breakage or failure of the filament with consequent short lamp life.

It is an object of my invention therefore to provide an electric incandescent lamp having its fllament so supported as to avoid detrimental eilects of lamp vibration or impacts.

Another object of my invention is to provide an electric incandescent lamp having a flexible mount structure of simple form and which will eiifectively withstand vibration and impacts to which the lamp may be subjected in service.

Further objects and advantages of my invention will appear from the following description of a species thereof and from the accompanying drawing.

Inthedrawing,Fig.1isasectionalviewofan electric incandescent lamp accordingto the invention; Fig. 2 is an enlarged perspective view of the lamp mount structure, with a portion thereof partly broken away to more clearly illustrate the invention; and Fig. 3 is an enlarged fragmentary view in section of a modifled form of mount structure comprising my invention.

In accordance with the invention, the filamentsupporting end or section of an electric incandescent lamp mount is rendered flexible in all directions by forming each of the lead-in wiresor inleads, inwardly of the lamp envelope, in two individual sections and electrically and mechanically connecting them together in longitudinally aligned and separated end-to-end relation by a coil spring fitted over and bridging the gap between the separated ends of the two inlead secflons and elastically gripp tly the said inlead sections.

Referring to the drawing, the invention is there shown as applied to an electric incandescent lampofthesealedbeamtypedisclosedinlls. Patent 2,148,314, D. K. Wright, and comprising asealedglassenvelopeorbulb I consistingof silver or other similar light-reflective material.

Mounted on the rear outer side of the reflector section 2 at the region of the apex or center thereof is a base structure I of the general type shown and described in U. 8. Patent 2,272,512, Cotman, and comprising a pair of terminal contacts 8-2 in the form of metal straps or lugs which are suitably fastened, as by soldering for instance, to the close nippled ends 9 of respective metal ferrules or thimbles II!II. The contact lugs 88 are provided with screw terminals I |-I I for connecting current supply wires thereto. The ferrules Iii-II are formed of a suitable metal which will readily "wet and adhere to the glass of the reflector section 2 and they are provided with skirt portions I: which are feathered to knife edges embedded and fused in the glass of the reflector section 2 around respective openings or passageways I3 through the wall thereof. The envelope I is provided with an exhaust tubulation ll communicating with the interior of the envelope through an exhaust opening IS in the envelope wall at the apex of the reflector section 2. After exhaustion of the envelope through the tubulation I4 and. is, desired, introduction of a suitable gas filling such as nitrogen or argon, the tubulation I4 is sealed or tipped-oil! as indicated at Ii.

Mounted within the envelope I and supported solely from the metal ferrules II in spaced relation to the envelope wall is a lamp mount structure I I according to the invention and comprising a pair of lead-in conductors or inleads Ill8 secured at their outermost ends within the nipples 9 of the ferrules, as by solder I! as shown. From the ferrules II, the lead-in conductors I2 extend through the openings ii in the wall of the reflector section 2 and into the envelope I in more or less parallel spaced relation and are connected at their innermost ends to the opposite ends of a filament 2| preferably in the form of a coiled wire of tungsten or other suitable refractory metal. In the specific case illustrated in Figs. 1 and 2, the filament 2| comprises a linear coil of tungsten wire having an opened center coil convolution 2| and extending transversely between the inner ends of the lead-in conductors II and mounted in the envelope I transversely of preformed presed glass reflector and cover glass ll theaxis of the reflecting surface t and approximately centered at the focus thereof. The filament 20 is additionally supported in place by means of a supplementary support or anchor wire 22 which is formed at one end with a book 23 within which the opened center convolution 2| is hooked. The other end of the filament anchor wire 22 is suitably fastened in place on an insulated part of the mount structure in a manner to be hereinafter described.

In accordance with the invention, the lead-in conductors or inleads !8l8 are each comprised of two separate wire sections 24 and 26 (i. e., an inner section 24 and an outer section 25) yieldingly held together in separated end-to-end relation and electrically connected by a coil spring or wire coil 26 fitted over and elastically gripping tightly the contiguous P rtions of the conductor sections 24, 25. The wire coils 26 are made of a material, such as tungsten, molybdenum or spring steel for instance, which will not lose its temper or springy character at the high temperatures encountered during operation of the lamp, and they are formed to an inside diameter slightly smaller (i. e., 2 or 3 thousandths of an inch) than the diameter of the wire conductor sections 24, so that they cannot he slipped over the said conductor sections but can only be fitted thereover by screwing the wire coils thereonto. In such manner, a firm and tight elastic grip of the wire coils 26 on the wire conductor sections is provided whereby the two separated sections 24, 25 of each conductor is are firmly held together in spaced end-to-end relation and a good electrical connection formed between the separated conductor sections and their interconnecting wire coils. The portions 2'! of the coil springs 26 bridging the gap between the separated conductor sections 24 and 25, being free to flex or bend in any direction because of the absence of any stiffener or filler member therein, therefore provide a yieldable connection between the conductor sections 24, 25 which serves to impart flexibility in substantially all directions (i. e., 360 solid angle) to the filament-supporting end of the mount Il whereby any vibrations or shocks to which the lamp may be subjected in service are efiectively absorbed or cushioned by such yieldable connecting sections 21.

The characteristics of the coil springs 26 employed and the spacing of the conductor sections 24, 25 are so selected as to support the filament 20 firmly in place in the envelope lwhile imparting the desired degree of flexibility to the upper section of the mount to absorb the vibrations and shocks incident to the normal usage of the lamp without causing undue filament movement and resultant wavering of the light beam emitted by the lamp. In the specific case illustrated, the individual wire sections 24 and 25 of the lead-in conductors I8 are made of approximately 50 mil diameter nickel wire and are separated end-toend a distance of approximately 2 mm., while the wire coils 26 are made of approximately 15 mil tungsten wire coiled to an inside diameter of approximately 48 mils.

To maintain the points of support of the filament in fixed relation to each other at all times independent of any unitary movement thereof due to lamp vibration or shock, the inner sections 24 of the conductors i8 are rigidly tied together and held in proper relation by suitable insulative timemeans which, in the particular case shown, comprises a cross-bar or bridge 28 consisting of a short length of glass rod 29 having a pair of support wires 30 embedded in and projecting from each of its ends. The cross-bar 23 is secured to the inner conductor sections 24 by suitably fastening each pair of its support wires 30, as by welding for instance, to the inner conductor sections 24 at spaced points therealong, as shown. The supplementary support or anchor wire 22 for the filament 20 is embedded and anchored in the glass rod 29 of the cross-bar, thus maintaining the intermediate support point for the filament in fixed relation to the end supports thereof at all times. The mount structure l1 according to the invention therefore includes as a part thereof a filament-supporting section or unit, comprising the inner conductor sections 24, the cross-bar 28 and the intermediate support wire 22, which holds the filament 20 in proper relation at all times and which is capable of moving as a unit, without relative movement between the filament and the adjacent supporting parts of the said unit. during vibration or other sudden movement of the lamp.

While the wire coils 26 are effectively prevented from moving or creeping along the conductor sections 24, 25 by reason of their tight elastic grip thereon, it is preferable to fixedly secure the said wire coils in place on the conductor sections. For this .purpose, the wire coils 26 may be made of sufiicient length to extend over substantially the full length of the outer conductor sections 25 so as to be embedded in the solder mass 19 which anchors the said outer conductor sections in the ferrules l6, thus holding the wire coils in place on the outer conductor sections. The inner ends of the wire coils 26 may be fastened in place on the inner conductor sections 24 by extending the said coils underneath at least the nearest ones of the support wires 30 of the insulating bridge or cross-bar 28 so as to be welded along with the said bridge support wires to the irmer conductor sections.

Instead of employing coil springs of true helical form throughout their length as shown in Figs. 1 and 2, they may be provided with an intermediate portion 3I of greater flexibility than their other portions and located at and bridging the gap between the separated sections 24, 25 oi the lead-in conductors l8, as shown in the modification .of Fig. 3. These more flexible intermediate portions 3| of the coil springs may be constituted by an enlarged diameter coil portion such as shown in Fig. 3, or by an opened coil portioi: or other such varied shape coil portion. These enlarged diameter or other varied shaped intermediate coil portions 3| impart a greater degree of flexibility to the mount structure l1 and therefore may be used where such added flexibilit: is desirable. The modification of Fig. 3 also illustrates the application of the invention to the support of a modified form of filament 32 comprising a plurality of more or less side-by-side coileC sections 33 joined by loops or bights 34 and lyini in a plane approximately coinciding with that o; the inner conductor sections 24. The filament 31 is connected at its ends to the conductor section: 24 and is supported at the bights 34 by ancho1 wires 35 formed at one end with hooks 36 withir which the filament bights 34 are hooked. Th1 other ends of. the anchor wires 36 are embeddel in the glass insulating members 31 of upper an: lower bridges or cross-bars 38 and 39, respectively, which are connected across the inner conductor sections 24 to rigidly tie them together.

From the foregoing it will be evident that thi mount structure I! comprising my invention pro vides a simple and eflective fiexible supportin;

ILGO'LUO? arrangement for the filament whereby any vibrations, jars or impacts to which the lamp may be subjected in service are readily absorbed by the yielding intermediate coil spring portions 21 or Ii of the lead-in conductors which act as an elastic connection or cushion between the inner or filament-supporting section of the mount and the anchored outer conductor sections 25 to efiectively minimize distortion of the hot filament by such lamp vibrations or shocks, thus rendering the entire lamp structure especially useful for rough service applications such as a locomotive headlight or as a lighting unit for automatic mining or earth moving equipment, tractors and other similar equipment where the lamp is ordinarily subjected to unusual shock or vibration.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An electric lamp comprising an envelope, a filament in said envelope, lead-in conductors anchored to and supported from the wall of said envelope and extending into the envelope from their wall anchorages in spaced relation to the envelope well, said conductors each comprising separate inner and outer sections spaced apart end-to-end and the filament being supported from and electrically connected to said inner sections, bridge means insulatively and rigidly tying the said inner conductor sections together,

and a coil spring fitting over and gripping tightly the individual sections of each of said conductors and bridging the gap therebetween to yieldingly hold and electrically connect the said conductor sections together whereby to resiliently support the filament and inner conductor sections from the anchored outer conductor sections.

2. An electric lamp comprising an envelope, 1 filament in said envelope, lead-in conductors anchored to and supported from the wall of said envelope and extending into the envelope from their wall anchorages in the same general direction and in spaced relation to the envelope wall, said conductors each comprising separate inner and outer sections spaced apart end-to-end and the filament being supported from and electrically connected to said inner sections, bridge means insulatively and rigidly tying the said inner conductor sections together, and a coil spring fitting over and elastically gripping tightly the individual sections of each of said conductors and bridging the gap therebetween to yieldlngly hold and electrically connect the said conductor sections together whereby to resiliently support the filament and inner conductor sections from the anchored outer conductor sections.

3. An electric lamp of the character set forth in claim 1 wherein the portions of the said coil springs bridging the gap between the separated conductor sections are of greater flexibility than the other portions thereof.

4. An electric lamp of the character set forth in claim 1 wherein the portions of the said coil springs bridging the gap between the separated conductor sections are of enlarged coil diameter.

5. An electric lamp of the character set forth in claim 1 wherein the coil springs are each fixedly secured to their respective inner and outer conductor sections.

JOSEPH E. STONE.

No references cited. 

